arm: Fix CMSE clearing of union members with no padding [PR122539]

This patch fixes the CMSE register clearing to make sure we don't clear
registers used by a function call.  Before this patch the algorithm would only
correctly handle registers with padding bits to clear, any registers that were
fully utilised would be wrongfully cleared.

gcc/ChangeLog:

	PR target/122539
	* config/arm/arm.cc (comp_not_to_clear_mask_str_un): Update
	not_to_clear_reg_mask for union members.

gcc/testsuite/ChangeLog:

	* gcc.target/arm/cmse/union-3.x: New test.
	* gcc.target/arm/cmse/baseline/union-3.c: New test.
	* gcc.target/arm/cmse/mainline/8m/union-3.c: New test.
	* gcc.target/arm/cmse/mainline/8_1m/union-3.c: New test.

diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
index 6df2fa02172c0aeb7c1db688ecb7c746dfac3be5..bd1f6e0133ab7edd73ab333772fafd3fd7e49753 100644 (file)
--- a/gcc/config/arm/arm.cc
+++ b/gcc/config/arm/arm.cc
@@ -18628,6 +18628,9 @@ comp_not_to_clear_mask_str_un (tree arg_type, int * regno,
       padding_bits_to_clear[max_reg]
        |= padding_bits_to_clear_res[max_reg] & mask;
 
+      for (int i = *regno; i < max_reg; ++i)
+       not_to_clear_reg_mask |= HOST_WIDE_INT_1U << i;
+
       *regno = max_reg;
       *last_used_bit = max_bit;
     }

diff --git a/gcc/testsuite/gcc.target/arm/cmse/baseline/union-3.c b/gcc/testsuite/gcc.target/arm/cmse/baseline/union-3.c
new file mode 100644 (file)
index 0000000..f68a081
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/cmse/baseline/union-3.c
@@ -0,0 +1,29 @@
+
+/* { dg-do compile } */
+/* { dg-options "-mcmse" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+#include "../union-3.x"
+
+/*
+** fn_caller_0:
+** ...
+**     lsrs    r4, r4, #1
+**     lsls    r4, r4, #1
+**     movs    r2, r4
+**     movs    r3, r4
+**     bl      __gnu_cmse_nonsecure_call
+** ...
+*/
+
+/*
+** fn_caller_1:
+** ...
+**     lsrs    r4, r4, #1
+**     lsls    r4, r4, #1
+**     movs    r1, r4
+**     movs    r2, r4
+**     movs    r3, r4
+**     bl      __gnu_cmse_nonsecure_call
+** ...
+*/

diff --git a/gcc/testsuite/gcc.target/arm/cmse/mainline/8_1m/union-3.c b/gcc/testsuite/gcc.target/arm/cmse/mainline/8_1m/union-3.c
new file mode 100644 (file)
index 0000000..022bef7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/cmse/mainline/8_1m/union-3.c
@@ -0,0 +1,32 @@
+
+/* { dg-do compile } */
+/* { dg-options "-mcmse" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+#include "../../union-3.x"
+
+/*
+** fn_caller_0:
+** ...
+**     lsrs    r3, r3, #1
+**     lsls    r3, r3, #1
+**     push    {r4, r5, r6, r7, r8, r9, r10, fp}
+This test is not meant to be to test the FP clearing, so accept any, preventing
+the need to specialize the test further for different float-abi's
+** ...
+**     clrm    {r2, r4, r5, r6, r7, r8, r9, r10, fp, ip, APSR}
+**     blxns   r3
+** ...
+*/
+
+/*
+** fn_caller_1:
+** ...
+**     lsrs    r3, r3, #1
+**     lsls    r3, r3, #1
+**     push    {r4, r5, r6, r7, r8, r9, r10, fp}
+** ...
+**     clrm    {r1, r2, r4, r5, r6, r7, r8, r9, r10, fp, ip, APSR}
+**     blxns   r3
+** ...
+*/

diff --git a/gcc/testsuite/gcc.target/arm/cmse/mainline/8m/union-3.c b/gcc/testsuite/gcc.target/arm/cmse/mainline/8m/union-3.c
new file mode 100644 (file)
index 0000000..dd115b4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/cmse/mainline/8m/union-3.c
@@ -0,0 +1,33 @@
+
+/* { dg-do compile } */
+/* { dg-options "-mcmse" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+#include "../../union-3.x"
+
+/*
+** fn_caller_0:
+** ...
+**     lsrs    r4, r4, #1
+**     lsls    r4, r4, #1
+**     mov     r2, r4
+**     mov     r3, r4
+This test is not meant to be to test the FP clearing, so accept any, preventing
+the need to specialize the test further for different float-abi's
+** ...
+**     bl      __gnu_cmse_nonsecure_call
+** ...
+*/
+
+/*
+** fn_caller_1:
+** ...
+**     lsrs    r4, r4, #1
+**     lsls    r4, r4, #1
+**     mov     r1, r4
+**     mov     r2, r4
+**     mov     r3, r4
+** ...
+**     bl      __gnu_cmse_nonsecure_call
+** ...
+*/

diff --git a/gcc/testsuite/gcc.target/arm/cmse/union-3.x b/gcc/testsuite/gcc.target/arm/cmse/union-3.x
new file mode 100644 (file)
index 0000000..880ceb4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/cmse/union-3.x
@@ -0,0 +1,23 @@
+#include <arm_cmse.h>
+
+union u_t_0 {
+  long long ll;
+};
+
+typedef void(__attribute__((cmse_nonsecure_call)) fn_t_0)(union u_t_0);
+
+void fn_caller_0(fn_t_0 *f_ptr) {
+  union u_t_0 x = {1234};
+  f_ptr(x);
+}
+
+union u_t_1 {
+  long int l;
+};
+
+typedef void(__attribute__((cmse_nonsecure_call)) fn_t_1)(union u_t_1);
+
+void fn_caller_1(fn_t_1 *f_ptr) {
+  union u_t_1 x = {1234};
+  f_ptr(x);
+}